US 2012O195842A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2012/0195842 A1 Meyer et al. (43) Pub. Date: Aug. 2, 2012 (54) ENHANCED PHOTOSTABILITY OF Publication Classification SUNCARE COMPOSITIONS CONTAINING AVOBENZONE (51) Int. Cl. A61K 8/44 (2006.01) (76) Inventors: Thomas A. Meyer, Germantown, A61O 1704 (2006.01) TN (US); Donathan G. Beasley, CD7C 45/86 (2006.01) Memphis, TN (US) (52) U.S. Cl. .............................. 424/60; 568/304; 424/59 (21) Appl. No.: 13/443,587 (57) ABSTRACT (22) Filed: Apr. 10, 2012 The invention provides compositions and methods for Related U.S. Application Data enhancing the photostability of avobenzone in compositions for topical administration, including, e.g., Sunscreen compo (62) Division of application No. 12/392.465, filed on Feb. sitions, by addition of methyl anthranilate in an amount effec 25, 2009. tive to stabilize avobenzone against photodegradation par (60) Provisional application No. 61/031,950, filed on Feb. ticularly where the composition is substantially free of other 27, 2008. non-Sunscreen agents that photostabilize avobenzone. US 2012/0 195842 A1 Aug. 2, 2012 ENHANCED PHOTOSTABILITY OF when it is combined with zinc oxide and that avobenzone's SUNCARE COMPOSITIONS CONTAINING photostability could be enhanced by addition of phenylben AVOBENZONE Zimidazole Sulfonic acid. SUMMARY FIELD OF THE INVENTION 0007. Applicants have found that sunscreen active men 0001. Some example embodiments of the present inven thyl anthranilate, also known as meradimate, can enhance tion generally relate to compositions for skin application to photostability of avobenzone in Sunscreen compositions protect against harmful effects of ultraviolet radiation, par exposed to UV radiation for extended periods of time. Impor ticularly the effects of solar radiation. This application claims tantly, this result is demonstrated in the absence of other priority from U.S. provisional patent application Ser. No. agents used to photostabilize avobenzone. Such as phenylben 61/031,950 filed Feb. 27, 2008. Zimidazole Sulfonic acid. 0008. One example embodiment of the invention encom passes a composition including avobenzone and menthyl BACKGROUND anthranilate, wherein menthyl anthranilate is present in a Sufficient amount to stabilize the avobenzone against photo 0002 Avobenzone (trade names Parsol R, 1789, Eusolex(R) degradation. 9020, EscalolR 517 and others, INCI Butyl Methoxydiben 0009. Another example embodiment of the invention Zoylmethane) is an oil soluble ingredient used in Sunscreen encompasses a method for protecting the skin against ultra products to absorb the full spectrum of UV-A rays. It is a violet radiation, including applying to the skin an effective dibenzoylmethane derivative. Its ability to absorb ultraviolet amount of a composition comprising avobenzone and men light over a wider range of UVA wavelengths than many thyl anthranilate, whereinmenthyl anthranilate is present in a organic Sunscreen agents has led to its use in many commer Sufficient amount to stabilize the avobenzone against photo cial preparations marketed as “broad spectrum Sunscreens. degradation. 0003 AVobenzone has the chemical name 1-(4-methox 0010 Yet another example embodiment of the invention yphenyl)-3-(4-tert-butylphenyl)propane-1,3-dione (CAS encompasses a method for improving the photostability of Registry No. 70356-09-1). The molecular weight of avoben avobenzone in a composition including avobenzone and men Zone is 310.39 and it has the following chemical structure: thyl anthranilate, whereinmenthyl anthranilate is present in a Sufficient amount to stabilize the avobenzone against photo degradation. DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS HC CH 0011 Sunscreening compositions generally are permitted 3 No to contain only the active ingredients that have been approved CH by governmental authorities, and frequently those authorities H3C also specify the amounts of each approved ingredient that are permitted to be present in a product. For purposes of the 0004 AVobenzone, as a sunscreen active, has potential to present invention, a 'sunscreen active agent” or 'sunscreen degrade chemically when exposed to ultraviolet radiation active' shall include all of those materials, singly or in com (UVR) after prolonged exposure, e.g., become photoun bination, that are regarded as acceptable for use as active Sunscreening ingredients based on their ability to absorb and/ stable. Chemical degradation robs avobenzone of its ability to or dissipate UV radiation. Such compounds are generally absorb UVR and hence destroys its ability to protect skin described as being UV-A, UV-B, or UV-A/UV-B active against damaging UV rays when it is used as a Sunscreen agents. Approval by a regulatory agency is generally required active in Sunscreen products. AVobenzone can be maintained for inclusion of active agents in formulations intended for intact chemically as an absorber of UVR simply by adopting human use. Those active agents which have been or are cur recognized formulation strategies to incorporate avobenzone rently approved for sunscreen use in the United States include into a sunscreen product. When formulated into a product organic and inorganic Substances including, without limita correctly, avobenzone remains intact chemically even over tion, para aminobenzoic acid, avobenzone, cinoxate, dioxy prolonged exposures to UVR. benZone, homosalate, octocrylene, octyl methoxycinnamate, 0005 Formulation strategies to optimize avobenzone's octyl salicylate, oxybenzone, padimate O. phenylbenzimida photostability include (1) removal of incompatible ingredi Zole Sulfonic acid, Sulisobenzone, trolamine salicylate, tita ents, like octinoxate; (2) leveraging other Sunscreen actives nium dioxide, Zinc oxide, diethanolamine methoxycin for their ability to enhance avobenzone's photostability; and namate, digalloy trioleate, ethyl dihydroxypropyl PABA, (3) using non-sunscreen ingredients that have capacity to glyceryl aminobenzoate, lawsone with dihydroxyacetone, photostabilize avobenzone through energy transfer mecha red petrolatum. Examples of additional Sunscreen actives that nisms, such as diethylhexyl-2,6-napthalate (known as Cora have not yet been approved in the U.S. but are allowed in pan R TO) or diethylsyringylidene malonate (known as formulations sold outside of the U.S. include ethylhexyl tria Oxynex(RST). Zone, dioctylbutamido triaZone, benzylidene malonate pol 0006 U.S. Pat. No. 7,244,416, titled “Stabilized Photo ysiloxane, terephthalylidenedicamphor Sulfonic acid, diso protective Composition' to Meyer etal, generally describes a dium phenyl dibenzimidazole tetrasulfonate, diethylamino decrease in the photostability of avobenzone, particularly hydroxybenzoyl hexyl benzoate, bis diethylamino hydroxy US 2012/0 195842 A1 Aug. 2, 2012 benzoyl benzoate, bis benzoxazoylphenyl ethylhexylimino 0016 (C2HNO275.39) and is also referred to as men triazine, drometrizole trisiloxane, methylene bis-benzotriaz thyl-O-aminobenzoate and anthranilic acid, p-menth-3-yl olyl tetramethylbutylphenol, and bis-ethylhexyloxyphenol ester. methoxyphenyltriazine, 4-methylbenzylidenecamphor, and 0017. The inventors have surprisingly discovered that isopentyl 4-methoxycinnamate. However, as the list of when menthyl anthranilate is present in a sufficient amount, approved Sunscreens is currently expanding, those of ordi avobenzone's photostability is increased even over long nary skill will recognize that the invention is not limited to exposures to ultraviolet radiation. The increased photostabil Sunscreen active agents currently approved for human use but ity results are unexpected in view of the fact that menthyl is readily applicable to those that may be allowed in the anthranilate's chemical structure, a derivative of amino ben future. Zoate, is similar to Sunscreen actives that are known to desta 0012 Section 352.20 of the same Title 21 describes the bilize avobenzone, such as PABA and Padimate O, which are permitted combinations of ingredients; in general, each active para-amino benzonates. In comparison, menthyl anthranilate ingredient in a permitted combination is required to be is an ortho-amino benzoate. present in at least a sufficient amount to contribute an SPF 0018. The composition can also contain an emulsifier, value of 2. So an amount making this contribution is consid typically hydrogenated palm glycerides or Cs-C fatty alco ered herein to be the minimum “sunscreening-effective' con hols. Preferably, the Cs-C fatty alcohol is capry alcohol, centration of an active ingredient. The regulations prescribe capic alcohol, myristyl alcohol, cetyl alcohol, Stearyl alcohol, maximum concentrations of 3 percent avobenzone, and 25 arachidyl alcohol, or cetearyl alcohol. The emulsifier can also percent zinc oxide. Some countries allow the use of other be a phosphate-based emulsifiers such as potassium octyl active ingredients noted above and these are also suitable for phosphate, potassium nonyl phosphate, potassium decyl inclusion as components of the compositions of this inven phosphate, potassium undecyl phosphate, potassium lauryl tion. In addition, the permitted concentrations of active ingre phosphate, potassium myristyl phosphate, potassium cetyl dients vary somewhat by country. phosphate, potassium Stearyl phosphate, dicetyl phosphate, 0013 The official adopted name in the United States for ceteth-10 phosphate, ceteth-20 phosphate, or ceteth-30 phos octyl methoxycinnamate is “octinoxate, and the official phate. More